Art of mixing concrete and transporting the same



Sept. 11, 1928.

Re. K. SCHUSTER ART OF MIXING CONCRETE AND TRANSPORTING THE SAME Original Filed April 4, 1916 l VENTOR ATTORNEY Reissued Sept. 11, 1928.

UNITED STATES v Re.17,o3z PATENT OFFICE.

-KARL It. SCHUSTER, OF HOPATCONG, NEW JERSEY.

ART or MIXING concanrn AND 'rnmsronrme rnn snmn.

Original No. 1,553,476, dated September 15, 1925,'Ser1a1 lie. 88,770, filed April 4, 1916. Applicati'on for reissue filed December 23, 1926. Serial No. 156,747. I

' This invention pertains to the art of mixing concrete and transporting the same to the place where said material is to be utilized in the installation of concrete structures of one form or another.

The objects of the invention are to expedite the mixture of the materials, to attain a su perior admixture within a few minutes time, and to feed or transport the material from the mixing cont-rivance, all of which results in substantial economy of the operations.

To these ends, the first part of my invent-ion involves the use of air or other gas under pressure and controlled in such a way as to effect both the admixture of the materials and the feeding or transportation of the resulting concrete. Accordingly, the operations include the depositing of the material, (sand, a mineral aggregate and cement with suflicient water) within a closed chamber; adinitting air, steamer other gas to the lower part of such chamber, whereby the air or gas blown into the chamber exerts pr'essure uponthe materials so as to blow the same upwardly within the chamber and thereby agitate said materials to secure the desired admixture thereof; then accumulat-in the air or gas within s'aidchamber until the air or gas pressure.

upon the mixed materials is equal substantially to the pressure of the current blown into the bottom part of said chamber; then shutting off the pressure of the inflowing air ongas while retaining the pressurewithin the chamher; then opening the outlet from the bottom of the chamber so as to supplement the gravity or weight of the mass bythe pressure of air or gas Within the chamber, thereby displacing the mass of materials from said chamber and ber for feeding air or gas thereinto and under a pressure sufficient to effect the-admixture of the materials and the displacement of the resulting mixed mass of concrete; and a valve for closing the outlet at the time the air or gas is blown into the chamber. From the bottom of thechamber a conduit extends to the point at which the concrete is to be utilized, and if necessary a second pressure pipe is connected with sald conduit for. blowing air or gas into the same to supplement the pressure of the gas or air admitted initially and thereby effect the movement of the mass of concrete should itbe found necessary to transport the latter for along distance.

Other features and advantages of the invention will appear from the following description taken in connection with the draw- .ing, whereinthefigure shown is a vertical section through an apparatus for mixing andtransporting concrete in accordance with this invention.

A designates a, tank or hopper, the lower I part a of which is of inverted conical form, whereas the upper part 'a is dome-shaped. The tank is provided with a mouth member B of flaring form having a charging opening I), the latter being normally closed bya gatevalve C. The mouth and. the valve are mutually constructed to secure a tight joint around the charging opening in order to preclude the escape of air or gas and toefi'ect the accumulation of the air or gas blown into the chamber of the tank. Any suitable means may be employed for. the operation of the gate-valve and to retain the latter in a tightly closed relation to the charging mouth, but, as shown herein, said gate-valve'is hung on a' rockshaft c, to one end of which is attached an externally pos'itioned lever 0 having a weight 0 The lever provides convenient means for opening the valve in order to lIl-"x trodurfe the materials into the tank, but when the lever is released, the weight 0 presses the valve tightly against the mouthpiece B.

Attached to the lower part of the tapering member a is a fitting 1), the same providing an outlet (1 leading from the lower part of the tank or receptacle tp an elbow e of a conduit E, the'latter extending from the tank 'or receptacle to the placewhere the mass of concrete isto be used in the construction of buildings, etc'. The fitting D isprovided at one side thereof with a nipple f from which extends a passage fleading upwardly within the fitting and opening into the chamber of the tank or receptacle A. The pressure pipe F is coupled in a suitable way to the nipple f, said pipe being adapted tofeed air or gas under pressure through the passage f in a manner to direct the inflowing pressure of air or gas upwardly into the material present within the tank, said inflowing air or gas being directly upwardly into contact with the mate-' rial and flowing into "the mixing chamber above the mixture outlet cl. The area of the air inlet is considerably less than the area of the outlet 0! for the mixture; furthermore,

- corporated with the sand and cement. The

mixture outlet thus afl'ords an unobstructed opening for the mixed material, and the gas or air is supplied under pressure and at the re uired velocity upwardly'into the chamber, anal flows through the passage 7" and upwardly into the mixing chamber and above the mixture outlet, for agitating the materials to properly effect the mixture thereof. The pressure pipe -F should, obviously, be connected with a pressure reservoir into which air or gas is forced by any suitable compressor so as to maintain a pressureof 80 lbs, more or less, as may be found necessary in the operation of the apparatus.

tioned opposite the outlet of pressure pipeF.

The battle extends upwardly into the space or chamber of fitting D, one surface 9 of the baffle being curved as, shown for the purpose of directing the inflowing air or gas in an upward path into the tank. The battle G is formed with a recess 9 adapted to produce a shoulder 9 and within .this recess is fitted a heel h of a valve H, the latter being normally positioned across the outlet from the bottom of the hopper. tached to a rockshaft I, the end portions of which are supported in suitable bearings provided in the fitting D, and, as will be readily understood, this rockshaft is provided with suitable means whereby the shaft may be rocked either by hand or power so as to impart a swinging movement to the valve H.

In the operation of mixing the material and of accumulating air or gas pressure within the tank, valve H occupies the raised position shown in full lines in the drawings so as to cut off the outflow of the mass of material and to retain the air ,or gas within the tank, but after the mixture of the materials shall have been effected within the tank, the rockshaft I is turned so as to move the valve H into the position shown in dotted lines in the drawing. The outlet from the hopper is thus opened for the material'to pass through the fitting D and elbow e into the conduit E, the valve H being positioned below the shoulder g of the battle and said valve lying close againsta wall of the fitting D so that said valve is substantially out of the path or line The fitting D is, I desirably, provided, also, with a baffie G, posi Said heel of the valve is atwithin the scope of the skilled constructor; I

have not considered it important to more particularly illustrate or' describe the special form of connection between the several parts of the apparatus.

The conduit E is of a length to extend from the mixing tank to theplace at which the concrete material is tobe utilized in construction work, and in some instances this conduit may be so long that the pressureof air or gas accumulated within the tank A is not sufiicient to effect the transportation of said concrete material'for the full length of said conduit. Under these and other circumstances, it is preferred to employ an additional pressure pipe J, which is coupled to a nipple j of the elbow e, whereby said pipe J is adapted to supply additional air or gas to the conduit E and rearwardly of the mass of material moving therein.

The operation isas follows The pressure pipes F,J, are closedby the operation of suitable stop cocks (not shown), and lever c is operated to open valve C, the valve H occupying the closed position shown in full lines. The materials, usually sand, cement, a mineral aggregate, and water in the required volumes, are poured through the opening I) of the charging mouth so as to accumulate within the tank A, and within the passage f, a batch of the materials to be mixed. The valve C is closed, if required,

and'is pressed tightly against the charging opening of the mouth B, and air or gas under pressure, of about lbs. to the square inch, is admittedto the lower part of the tank through the pipe F. The baffle G directs the inflow ng air -or gas upwardly and into and through the material comprising the batch,

whereby said .air or gas when initially admitted blows the material upwardly within the chamber of the tank for the purpose of effecting the admixture of said materials.

The air or gas accumulates within the upper part of the tank A and'above the mass of materials therein. The air or gas continues .to flow into the tank until the pressure in the upper chamber thereof becomes equal to the pressure of the inflowing air or gas, and at this time the mass ofmaterial is'in a quiescent or non-agitated condition. By accumulating the air or gas within thetaiikuntil it has attained a pressure in the upper part of the tank equal to the pressure of the inflowing air gas, instead of permitting the air or gas to escape out of the tank as in systems which have preceded 'my invention, I am enabled to utilize the air -or gas pressure in the expulsion of the mixed mass of materials from the tank and to transport said mixed materials through the conduit to the point where the concrete mixture is to be utilized, as a result of which economy of operation is obtained. The materials having been mixed within the tank, 'andair or gas having accumulated to about lbs. Within said tank and above the mass of materials, the operator should turn rock shaft I in order to move the valve H to the depending position close to a. wall of the fitting D, as shown in dotted lines, thus opening the outlet from the tank to the conduit. The weight or gravity of the mass of material, and the pressure of the air or gas upon the mass, effects a quick expulsion of the material from the tank, said material being forced through the conduit E by the pressure of the air or gas. Should the movement of the material be relatively slow, or should the material require transportation for a comparatively long distance, then additional air is supplied directly into the conduit E by the pressure pipe J.

My invention secures important functions in the method of and apparatus for mixing and transporting concrete by blowing compressed air or gas into the materials and into the mixture, whereby the admixture of such materials and the transportation of such mixture are effected pneumatically, for which purpose there is employed a vessel provided at its lower part with a mixture outlet independent of the compressedair inlet and the area of which exceeds the area of said compressed air'inlet, and which mixture outlet is controlled by a valve adapted to be closed during the inflowupwardly. of the compressed air for agitating and mixing the ma terials and which valve is opened for the out-- flow of the mixture, at which stage of the operations compressed air is blown into the mixture as it passes fromthe mixing vessel and into an off-bearing conduit. I

"As stated, the fluid pressure supply functions in a ,two-fold capacity in connection with a mixing vessel provided, at its bottom part with a mixture outlet and with a valve for controlling such outlet at the mixing stage of the operations, one function of such fluid pressure supply being to blow compressed air or gas upwardly within the mixing chamber and into the materials to be mixed, the discharge valve being closed at said mixing stage for precluding the outflow of the materials, and another .function being to blow compressed air into the mixture as it passes the discharge valve beingopen at the discharging stage. -The discharge valve at the bottom part of the mixing chamber opens apath for the; outflow of the mixed materials by gravity, and such outflow is dc-.

-sirably accelerated by pressure upon the mixed mass of air accumulated within the mixing chamber durin the upflow of such air through the materials at the mixing stage. Such pressure of air upon the mass tends to dislodge such mass from the chamber, and in the outflow of such mass from the chamber the compressed air flows with the material from the chamber into the offbearing conduit, Again, the compressed air blown into the mixture as the latter passes out of the :chamber and into the offbearing conduit, ac-

celerates the discharge of the mixture and acts on the components of such mixture to further agitate such components and to thus improve the mix.

The discharge valve H in one position is inclined for closing the mixture. outlet, as shown by full lines, and in a second position, indicated by dotted lines, said valve is out of line of flow of the mixture as it passes from the mixing chamber to the oflbearing 'conduit. In the first (closed) position of said discharge valve, it is inclined relatively to the vertical axis of the mixing chamber and to the compressed air inlet afford-ed by pipe F, and said valve when in said inclined position, fulfills the further function of means for directing inflowing fluid pressure, admitted by pipe F, upwardly into the mixing chamber, should any part of such inflowing fluid pressure pass by deflector G.

The area of the discharge opening, controlled by valve H, is greater than the area of the blast inlet afforded by pipe F, said discharge opening being relatively large, as shown, to provide for the unobstructed or free outflow of concrete whenthe valve H is components of the mass of concrete, to be mixed within the vessel.

I attach importance, to the use of the tank closed against the exit of air or gas and the outlet of the materials during the operation of, blowing air or gas under pressure into the tank, for the reason that I am thlereby enabled to efi'ect substantial economy in the mixing operation and in the subsequent transporting operation. By closing the tank against the egress of air or gas'while mixing the ingredients, it is apparent that the cement, introduced in a dry condition, is not blown out of said tank when the air or gas blast is turned on,thus efl'ecting afimaterial saving in the cement; and, further, the air'or gas isretained under pressure sothat after the I blast is first turned on the materials are from the mixing vessel and into the conduit,

mixed, and then become quiescent under the accumulated pressure, whereupon valve H is opened and all the mlxed mass is expelled effect the mixing and in the pressure utilized for transportin the mass.

In the operation of the apparatus so as to opened, but it is to be noted that duringthe no i by the accumulated pressure, thus effecting a substantial saving in the blast required to carry out the process of this invention, the inflow of air or gas, at the initial stage of mixing, operates to displace the ingredients of the mixture; but after a short time the mixt'ure attains a state of quiescence, due to the continued inflow of the air or gas and to the accumulation thereof within the upper part of the closed chamber. The air or gas, after,

the mixing is completed,"continues to flow into the chamber until the pressure therein above'the mixture is equal to the pressure at the feed pipe or substantially so, this condition being indicate to the user of the apparatus by the cesstion of flow from the feed pipe into the chamber or tank, or such indication may obviously be attained by any meanskn'own to those skilled in-the art, such, for example, as are aiiorded by a pressure gage or gages.

Having thus fully described the invention, whatI claim as new and desire to secure by Letters Patent is:

1. In the art of mixing and transporting concrete, the process which consists in accumulating ,the materials to be mixed within a closed chamber; blowing air 01' upwardly into contact with said materials for agitating and mixing the same and simultaneously with said inflow of air or gasirestraining the materials to preclude their exit from the chamber and restraining, also, the exitfrom said chamber of the inflowing air or-gas; continuing. the inflow of air or. gas upwardly through the material until it attains a desired pressure upon the mixed mass; releasing the mixed mass from restraint and expelling the same from said chamber solely by the pressure of air or gas accumulate-cl therein, and by'a continuance of said inflow of gas 40 and moving the mixed mass to a place of use by air or gas pressure applied to said mass. 2. In the art of mixing and transporting concrete, the process which consists in accumulating the materials to be mixed within a closed chamber; blowing air or gas under pressure upwardly within said chamber into contact with said materials for agitating and mixing the same and simultaneously therewith restrainingthe exit from said chamber additional air or gas-supplied rearwardly of the moving vmixed mass. '3. Ins-an apparatus-of the'class described, the combination of a chamber provided with a charging opening and at its bottom portion of the agitated materials and of the inflowing. air or gas; continuing to'feed air or gas un-' with an outlet, means for closing the charging opening against the escape of air or gas, means connected with said chamber for blowing air or gas therein, a valve operable to closethe out-let during the operation of blowing air or gas into the chamber, a bafile positioned intermediate the valve and the outlet from said blowingmeans, for directing the inflow-' ing air or gas upwardly within the chamber, and a conduit connected to the bottom part ofthe chambenfor the flow of the concrete mass therethrough upon opening the valve. 7.4. In an apparatus, of the class described. the combination of aclosed chamberprovided with a charging opening, an oil-bearing conduit connected to the bottom portion of said ,chamber and afi'ording an outlet for the mass therein, means for closing said charging opening whereby air or gas is precluded from escaping out of the chamber, a valve posi tioned for cutting off communication between the chamber and the otf-bearingconduit, means connected with said chamber for feeding air or gas upwardly into said chamber when said valve is closed, said valve being operable to open a path from the chamber to the conduit and thereby utilize the pressure of the accumulated air orgas in displacing themixture, and means for feeding air or gas into said conduit and rearwardly of the material moving through it.

5. An apparatus for mixing concrete and the like embodying a vessel provided at. its upper part with a charging opening, said vessel having at the lower part an outlet for 3 the mixture, means for insuring the i'nflow of air in an upward direction intothe mixture and above the mixture outlet, the area of said mixture outlet exceeding the area of the air inlet and\ afl'ording an unobstructed path for the free egress of the'mixed materials, and a valve for closing the mixture outlet at the mixing stage of the operation.

6. An apparatus for mixing concrete and the like, comprising-a vessel provided with an upper feed opening, a compressed air nozzle at the'lower part thereof having a fluid discharge opening of small r area than the said-upper opening, a mova ly-mounted valve at the lower part of the vessel, and an upwardly directed baflie interposed in the path of the air from said nozzle, said bafiie being independent ofthe said valve.

7. An apparatus for mixing and trans-- porting concrete and the like, comprising a vessel provided with an opening at the top, a conduit adapted for communication with the lower part of said vessel, means for admit-' ting fluid under pressure to the lower part of said vessel and the conduit, arid a memher at the lower part of said vessel opposite to the fluid pressure inlet to saidvessel, having a surface constructed to receive the impact of the fluid and to divert such fluid upwardly into the vessel.

8. An apparatus for mixing and transport 7 mg concrete and the like, comprising a ves-.-

sel having an opening at its upper part-and a valve controlled discharge opening in 'its lower part, a discharge cohduit communicating with said vessel through said opening in its lower part, means for feeding fluid under pressure to the conduit and 'to the vessel in proximity to the discharge opening in said vessel, and means for directing said fluid up-- wardly into said vessel when the said discharge opening is closed, said fluid feeding means being arranged to discharge fluid into the materials passing into said discharge conduit when the lower opening is opened.

9. An apparatus for mixing concrete and the like, comprising a Vessel provided with an upper opening, means for feeding fluid under pressure into the lower part of said vessel, a conduit connected with the lower part of the vessel and afl'ording means for the outflow of the mixture from said vessel, and a valve at the lower part of said vessel adjacent the inlet for the fluid pressure, said valve having an upwardly inclined surface adjacent said fluid inlet.

10. An apparatus for mixing concrete and. the like comprising a vessel provided with an upper charging opening and a lower discharging opening for the aggregates to be mixed, an off-bearing conduit connected for receiving the mixed aggregates from said discharging opening, fluid pressure means connected for communication with said vessel and said conduit and operable for feeding fluid under pressure into the aggregates for mixing the same and for feeding fluid into the mixed aggregates at the stage of the out flow thereof through said discharging opening, and a valve positioned adjacent the discharging opening for closing it during the mixing stage and operable to open an exit for the outflow of the mixed aggregates into the conduit i 11. The here-in described method of agitating. concrete or the like in a vessel and discharging it therefrom which consists in placing the concrete in the vessel, injecting compressed air thereinto upwardly from the bottom thereof, then permitting the concrete to pass in a stream like condition from the said vessel and simultaneously with such outflow injecting at the lower part of said vessel compressed air into the stream of the outflowing concrete, the direction of flow of the air so injected being in the same generaldirection as the stream like flow of the concrete.

1 2. The herein described method of agitate ing concrete or the like in a. vessel and discharging and conveying it therefrom which consists in placing the materials in the vessel, injecting compressed air thereinto from the lower part thereof, discharging from the lower part of the vessel the mixed materials,

and concurrently with such discharge injecting at the lower air into the out the concrete within the vessel, blowing co-m-' pressed air upwardly into the concrete present Within the vessel for'agitating and mixing the concrete, opening an outlet from the vessel, dislodging the mixture through said outlet by the air pressure within the vessel and by blowing compressed air into the concrete at substantially the point where said concrete flows out of said vessel.

1 1 In the art ofmixing concrete or like within a vessel and discharging it therefrom, the process which consists in placing concrete within the Vessel, blowing compressed air upwardly within. the vessel and into the cencrete for mixing the same, discharging the mixed-concrete in a stream like condition and by'gravity from said vessel,

from, the process which consists in placing the and concurrently with such gravity outflow dismdging the concrete by air-pressure within t; vessel and blowing air into the stream of flowing concrete emerging from said vessel.

15. In the art of mixing and discharging concrete, the process which consists in placing theconcrete within a. vessel, blowing compressed air upwardly within the vessel and into the concrete for agitating and mixing the same, discharging the mixed concrete from the bottom of said vessel and into a conduit, and blowing compressed air into the concrete substantially at the place where. said concrete flows out of the vessel and as it moves within said conduit. r a

16. In 't-he art of mixing and discharging concrete, the p-rocess which consists in plate ing concrete within a mixing vessel, discharging the mixed. concrete from said vessel and into a conduit, and blowing compressed air into said vessel at one stage and into the conduit at the subsequent stage during the outflowof said'concrete from the vessel for effecting the admixture of concrete within the vessel at the first stage and for effecting the transportation of the mixture within the conduit at the subsequent stage of the operations.

17. In an apparatus for mixing and transport-ing concrete, a mixing vessel provided with upper and lower openings, a valve for closing said lower opening, a conduit for re ceiving mixed concrete through said valved opening, means ,for blowing compressed air into the concrete within the vessel when said valve is closed, whereby the'concrete is agiwith an upper opening and a lower opening, v a conduit for receiving concrete through said lower opening, a valve for closing said lower opening, and means connected with the lower part of said vessel and with said conduit for blowing compressed air into theconcrete present within said vessel and into the concrete flowin from said vessel into said con-- duit, where y the concrete is mixed within the vessel when the valve'is closed and the outflow of the mixed concrete, when the valve is opened, is accelerated by compressed air blown directly into the outflowin g concrete at a level below the area at which the mixture is effected within the vessel.

19. In an apparatus for mixing and discharging concrete, a vessel, a conduit con nected to the lower part thereof, a valve for opening and closing the communication between the vessel and the conduit, means separate from the conduit for blowing compressed air upwardly within said vessel for effecting the admixture of the concrete when the valve is closed, and separate'means for blowing compressed air into concrete flowing from said vessel and into said conduit when said valve is opened, for propelling the mixed concrete within said conduit.

20. In the art of mixing and transporting concrete, the process which consists in mixing concrete within a vessel by blowing compressed air into the concrete present within the vessel, discharging the mixed concrete from the vessel ina path separate from the.

path of inflow of the compressed air into said vessel; and accelerating the outflow of the mixed concrete by'blowing compressed air into and within the outflowiii mixture and substantially in the direction 0 such' outflowing mixture.

21. In the art of mixing and transporting concrete, the rocess which consists in mixing concrete wit in a vessel by blowing commovement of pressed air into the concrete present within a vessel, discharging the mixed concrete in a stream like condition from the vessel, and accelerating the outflow of the concrete by blowing compressed air into the stream'like mixture substantially at the stage of its outflow from said vessel.

22. In an apparatus for mixing and discharging concrete, a mix ng vessel provided with an upper charging opening and a lower discharging opening, a conduit for receiving concrete through said discharging opening, a valve operable for arrestin the outflow of concrete through said discharging opening during the mixing stage of the concrete, and

means'for blowing compressed air into the said valve the concrete is mixed by the inflow I of compressed air and thereafter the outflow of the mixed concrete is accelerated by the compressed air blown into such outfiowing I concrete. a

23. In an apparatus for mixing and discharging concrete, a mixing vessel provided with an upper charging opening and a lower discharging opening, a conduit for receiving concrete through said discharging opening, a valve operable for arresting the outflow of concrete through said discharging opening during the mixing stage of the concrete, and means for blowing compressed air into said mixing vessel at the mixing stage and for blowing compressed air into the out-flowing concrete at a level below the zone at which the admixture of the aggregates is effected within said vessel, whereby the concrete is mixed within the vessel'b the inflowing com-1 pressed air and the outiibw ofthe concrete 24. In the art of mixing and transporting concrete, the process, which consists in placing the aggregates within a vessel, blowing compressed air within the vessel and into the aggregates for effecting the admixture thereof,

dischar in the mixed a re ates from the b b b 23 vessel, and accelerating the discharge by blowing compressed air into the.outflowing aggregates below'the level at *which the admixture is eflected within said vessel.

In testimony whereof I have hereto signed my name this 22nd day of December, 1926.

" KARL R. SCHUSTER. 

